<template>
    <div class="">
        <router-link tag="div" to="/" class="header-abs"
        v-show="showAbs">
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div class="header-fixed" v-show="!showAbs"
        :style="opacityStyle">
            <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
            景点详情
        </div>
    </div>
</template>
<script>
export default {
    name: 'DetailHeader',
    data () {
        return {
            showAbs: true,
            opacityStyle: {
                opacity: 0
            }
        }
    },
    methods: {
        handelScroll () {
            const top = document.documentElement.scrollTop
            if (top > 60) {
                let opacity = top / 140
                opacity = opacity > 1 ? 1 : opacity
                this.opacityStyle = {
                    opacity
                }
                this.showAbs = false
            } else {
                this.showAbs = true
            }
        }
    },
    activated () {
        window.addEventListener('scroll',this.handelScroll)
    },
    deactivated () {
        window.removeEventListener('scroll',this.handelScroll)
    }
}
</script>
<style lang="stylus" scoped>
    @import '~styles/varibles.styl'
    .header-abs
        position absolute
        left .2rem
        top .2rem
        width .8rem
        height .8rem
        border-radius .4rem
        line-height .8rem
        text-align center
        background rgba(0,0,0,.8)
        .header-abs-back
            color #fff
            font-size .4rem
    
    .header-fixed
        z-index 2
        position fixed
        top 0
        left 0
        right 0
        height $headerHeight
        line-height $headerHeight
        text-align center
        color #fff
        background $bgColor
        font-size .32rem
        .header-fixed-back
          position absolute
          top 0
          left 0
          width .64rem
          text-align :center
          font-size :.4rem
          color #fff
</style>